Running Rich
Thread Starter
Burning Brakes
Joined: Sep 2003
Posts: 1,107
Likes: 12
From: Baton Rouge, LA
Running Rich
'79 928 5-speed:
I've optimized and adjusted the fuel/air mixture until blue in the face and she still runs rich. Exhaust smells. Does this mean injector replacement / wur replacement. Anyone out there have some learning experiences to share.
BTW, the car feels like it could pull a house down and seems to be running good. Although, while in 3rd at approx. 1800-2000 rpm a small "flutter" is evident in the exhaust note. Haven't had a good chance to investigate, but at this point I assume its an exhaust leak (12 year old Ansa). I guess the relevance to my original question is would an injector with a poor spray pattern potentially cause this flutter -- poor combustion thus fuel carry-over into the exhaust.
I've optimized and adjusted the fuel/air mixture until blue in the face and she still runs rich. Exhaust smells. Does this mean injector replacement / wur replacement. Anyone out there have some learning experiences to share.
BTW, the car feels like it could pull a house down and seems to be running good. Although, while in 3rd at approx. 1800-2000 rpm a small "flutter" is evident in the exhaust note. Haven't had a good chance to investigate, but at this point I assume its an exhaust leak (12 year old Ansa). I guess the relevance to my original question is would an injector with a poor spray pattern potentially cause this flutter -- poor combustion thus fuel carry-over into the exhaust.
We had a choice?
Rennlist Member
Rennlist Member
Joined: Feb 2002
Posts: 18,952
Likes: 459
From: Texas
What are you using to "optimize" the air/fuel mixture? I use an air/fuel analyzer. Very little movement of the screw produces very large variations in the mixture on CIS equipped 928's. Sending you a PM.
Anthony Tate
79/928 Silver Metallic
Anthony Tate
79/928 Silver Metallic
Drifting
Joined: May 2001
Posts: 2,747
Likes: 3
From: Owasso, OK
Before you start replacing components, you should get a CIS pressure tester to check your control pressure, system pressure and leakdown. Your problem could be injectors, WUR, relief valve, bocked return line or a bad fuel distributor but it is impossible to pin it down without a proper test.
The A/F mixture can be set for driveability without a CO2 tester by slowly turning the adjuster clockwise (rich) until the engine starts to stumble. Mark the position and slowly turn it to lean (counterclockwise) until it misses or stumbles. Then move the adjuster to the mid point plus approximately 3 degrees rich. If you still smell gas in the exhaust then the system needs tested.
Dennis
The A/F mixture can be set for driveability without a CO2 tester by slowly turning the adjuster clockwise (rich) until the engine starts to stumble. Mark the position and slowly turn it to lean (counterclockwise) until it misses or stumbles. Then move the adjuster to the mid point plus approximately 3 degrees rich. If you still smell gas in the exhaust then the system needs tested.
Dennis